Resolve "Create networkpolicies for gitlab-runner"

Create networkpolicies for gitlab-runner
also add istio integration with PeerAuthentication and NetworkPolicy

related BB MR big-bang/bigbang!2581 (merged)

Closes #55 (closed)

chart/templates/bigbang/networkpolicies/egress-default-deny.yaml

+{{- if and .Values.networkPolicies.enabled (ne .Release.Namespace "gitlab") }}
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: egress-default-deny-{{ .Release.Name }}
+  namespace: {{ .Release.Namespace }}
+spec:
+  podSelector: {}
+  policyTypes:
+    - Egress
+  egress: []
+{{- end }}